Cruz-Martínez A, Arpa J
Unidad de Electromiografia, Hospital La Luz, Madrid, España.
Eur Neurol. 1997;38(2):82-7. doi: 10.1159/000113165.
Conduction time of the central motor pathways (CMCT) by transcranial magnetic stimulation (TMS) was performed within the first two weeks in 7 patients with isolated hemicerebellar lesions after stroke. Cerebellar infarcts were small (< 2 cm in diameter) in 5 patients and no brainstem structure was involved in CT studies. The threshold (3 cases) and CMCT (4 cases) were abnormal or asymmetric by stimulation of the motor cortex contralateral to the impaired hemicerebellum. The follow-up study in 2 patients revealed electrophysiological improvement closely related to clinical cerebellar recovery rate. CMCT was significantly longer by cortex stimulation contralateral to the impaired hemicerebellum than by ipsilateral stimulation. Prolonged CMCT was significantly correlated with the rated severity of cerebellar signs. Increased threshold may be due to depressed facilitating action of the deep cerebellar nuclei on contralateral motor cortex. Abnormal CMCT might result in reduced size and increased dispersion of the efferent volleys. Recovery of electrophysiological results could represent in part true potentially reversible functional deficit. Whichever the pathophysiological mechanisms involved, our results demonstrate that the cerebellum dysfunction plays a role in the abnormalities of CMCT elicited by TMS.
对7例中风后孤立性小脑半球病变患者在发病后两周内进行经颅磁刺激（TMS）以测定中枢运动传导通路（CMCT）的传导时间。5例患者为小脑梗死（直径<2 cm），CT检查未累及脑干结构。刺激患侧小脑半球对侧的运动皮层时，阈值（3例）和CMCT（4例）异常或不对称。对2例患者的随访研究显示，电生理改善与临床小脑恢复率密切相关。患侧小脑半球对侧皮层刺激的CMCT明显长于同侧刺激。CMCT延长与小脑体征的严重程度评分显著相关。阈值升高可能是由于小脑深部核团对侧运动皮层的易化作用减弱。CMCT异常可能导致传出冲动的大小减小和离散度增加。电生理结果的恢复可能部分代表真正潜在可逆的功能缺陷。无论涉及何种病理生理机制，我们的结果表明小脑功能障碍在TMS诱发的CMCT异常中起作用。
